1. Field of the Invention
The invention disclosed herein relates generally to the field of treating organic waste sludges to reduce and/or remove viable organisms and/or vector attraction, so that such sludges may be beneficially reused with safety. More particularly the invention disclosed herein relates processes for conversion of said sludges, which are inherently highly nutritious to plants, into a safe, enriched agricultural medium. With more particularity the invention relates to conversion of organic sludges into a form that may be easily handled, and have characteristics enhancing the ability of plants to extract nutrients from the rich organic materials included therein.
2. Description of Related Art
Organic waste sludges presently constitute a substantial problem in many areas of the world. Such wastes are by-products of municipal and private waste treatment plants, feed lot operations, sawmills, paper mills and other industrial operations wherein wastes of biological origin are intentionally collected for the purpose of treatment and/or secondarily aggregate as a consequence of a principal operation being conducted.
A problem with such organic sludges is that they provide an excellent growth medium for many types of potentially pathogenic bacteria, helminth ova and/or enteric viruses, which are almost inevitably introduced into said sludges by the influent waste stream. Because raw organic sludges frequently contain such potentially pathologic organisms they can be dangerous to human, animal and plant life, and proper disposal or reuse of said sludges presents a substantial problem.
Said sludges are also typically odoriferous, have substantial vector (pests, such as rats, mice, roaches and some birds) attraction, and exist in the form of a sticky, wet, cohesive mass. These characteristics substantially limit where untreated sludges may be acceptably disposed, entail the risk of vectors widely dispersing pathogens in the sludge, and make transportation and handling of the sludge difficult.
However, the very nutritious properties of organic sludge which cause potentially pathogenic organisms to flourish, also provide a potentially highly beneficial reuse for said sludge, as an agricultural enriching medium, provided that the potentially pathogenic organisms, vector attraction and difficult handling characteristics can be significantly improved.
A number of methods, described in 40 CFR Part 257, are known to reduce pathogens. These include aerobic digestion, anaerobic digestion, lime stabilization, air drying, composting, heat drying, heat treatment, gamma irradiation, electron irradiation and the methods shown on Table 6-1 of said regulation. In addition thereto U.S. Pat. Nos. 5,281,341 and 4,793,927 to Reimer's disclose methods for treating waste sludge with nitrous acid or ammonia.
All of the previously known methods involve one or more of the following disadvantages:
a) substantial time of treatment, PA1 b) high energy usage, PA1 c) use of complex, expensive, permanently located equipment, and/or, PA1 d) transport of pathogen bearing sludges to a permanently located treating facility.
The invention disclosed herein substantially reduces these disadvantages by providing a fast, simple, inexpensive method of disinfecting organic wastes, on site, with inexpensive chemicals and inexpensive, transportable, mechanical equipment. The invention further provides a process, and a composition produced thereby, for enhancing the nutritional value and physical characteristics of said composition as a plant medium/soil enriching agent.